Valve for rock drills



Nov. 18, 1930. w. A. SMITH. JR

VALVE FOR ROCK DRILLS Filed Dec. 12, 1929 INVENTOR. I

IIZEMIJ 1114212301171]? J3 BY fig 1115 A TTORNEY.

Patented Nov. 18, 1930 UNHTED STATES PATENT @FFICE WILLIAM A. SMITH, JR, or PrrrLLIPsBURs} NEW JERSEY, ASSIGNOR 'ro INGERSOLL- RAND COMPANY, or JERSEY CITY, N W JERSEY, A CORPORATION 03 NEW JERSEY V ALVE] EOE BOOK ,nRInLs Application filed December12, 1929. Serial No.'413,534. v

rapid and an eflicient distribution of the pres sure fluid to the cylinder and consequently a rapid action of the percussive element of the drill.

Other objects will be in part obvious and 1 in part pointed out hereinafter.

In the drawings illustrating the invention and in'which similar reference characters refor to similar parts,

Figure 1 is a sectional elevation of a rock drill equipped with a valve constructed in accordance with the practice of the invention and showing the valve and the piston in the positions which they will assume at the beginning of the working stroke of the piston, and

Figure 2 is a similar view showing valve in the reverse positions.

Referring more particularly to the drawing, A designates a cylinderhaving a piston chamber B in which is disposed a reciprocatory hammer piston O. The cylinder A has a free exhaust port D which i'scontrolled by the piston C. V v 7 A front cylinder washer E forms a closure for the front end of the piston chamber B and also serves to centralize a front head F with respect to the cylinder A. The front head F may serve as a guide for a working implement G which extends with its rear end into a cavity H in the front head to receive the blows of the hammer piston C which are transmitted to the working implement by an anvil block J disposed slidably in the front cylinder washer E.

In the rear end of the cylinder A is a valve chest comprising a'pair of plates K and L which are suitably bored to form a valve chamber 0. The plate K forms a closure for the rear end of the piston chamber B and supports the plate L upon which is seated a back head P.

The back head P and the front head F may be suitably secured to the cylinder Aas by means of the usual side bolts (not shown). Among other functions, the back head P the .serves'as a housing for a throttle valve Q of the rotary type having acham'ber R therein into which pressure fluid may-be constantly admitted from a source of supply. In the wall of the throttle valve Q is a port S which registers with a supply passage T in the back head and opening into a, rearward reduced portion U of the valve chamber 0. v

The admission of pressure fluid to the rear end of the piston chamber B for actuating the piston C forwardly is effected through a rear inlet passage V in the plate K, and from the reducedportion U of the valve chamber leads a front inlet passage W which is formed in the plates L and K and the cylinder A and opens into the front end of the piston chamber B. r a a r The inlet passages V and W are controlled by a distributing valve X in the valve chamber 0 having a body portion Y. A recess Z in the body portion Y is in constant communication-with the supply passage T and in the wall of the body portion Y is a passage 6 through which pressure fluid flows from the recess Z into the enlarged portion '0 of the valve chamber O.

Intermediate the ends. of the body portion Y is an integral guide flange d which, to-

gether with the rear end of the body portion,

0 of the valvechamber and the pressure fluid flowing to the rear inlet "passage V passes over the periphery of the head 6 while the pressure fluid flowing to the inlet passage W flows over the rear end of the body-portion Y.

In order to assure a rapid action of the valve X,-said-valve is provided with a pluare constantly exposed to pressure fiuidtendingto throw the valve. 7 To this end the rear end ofthe body portion Y is in the form of a pressure surface f against which pressure fluid acts tending to throw the valve forits initial position.

to assist the pressure fluid acting against the pressure surface 9 to throw the valve rear- Wardly. The valve X is accordingly pro vided at its front end with an actuating surface 71, which is adapted to seat over the inlet passage V and is intermittently exposed to compression from the rear end of the piston chamber. Leading from the rear end of the enlarged portion 0 to the atmosphere is a vent j to prevent the accumulation of pressure fluid rearwardly of the guide flange (Z.

The operation of the device is as follows: With the valve X and the piston C in the rearmost positions illustrated in Figure 1 pressure fluid will flow from the supply passage into the recess Z, thence through the passage or passages 6 into the valve chamber and across the periphery of the head 6 through the front end of the valve chamber and'the rear inlet passage V into the piston chamber to impel the piston C forwardly against the anvil block J.

The valve X will remain in the raisedposition until the rear end of the piston C "uncovers the exhaust port I). The front end of the valve chamber will then be in communication with the atmosphere so that there will be a suflicient drop in pressure in the enlarged portion of the valve chamber to enable the pressure acting against the pressure surface f, together with the suction created by the pressure fluid flowing over the edge of the head e, to throw the valve forwardly to the position illustrated in Figure 2.

In the new position of the valve the rear end of the body portion Y of the valve will uncover the front inlet passage IV so that pressure fluid will flow into the front end of the piston chamber to return the piston C to As the piston pr seeds rearwardly and after it has covered the exhaust port D, the air in the back end of the piston chamber B will be compressed and such compression will act against the actuating surface It to assist the pressure fluid acting against the pressure surface 9 to reverse the valve X. Pressure fluid may then flow to the back end of the piston chamber in the manner previously describedand the valve will be held rearwardly in the valve chamber by the pressure fluid acting against the actuating surface It and against the pressure surface g.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and a hammer piston therein, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, a valve in the valve chamber to control the inlet passages and having opposed differential pressure surfaces against which pressure fluid acts to throw the valve, a passage in the valve through WhlCll pressure fluid flows into the valve chamber, a head on the valve over which pressure fluid flows to one inlet passage, and

an actuating surface on the valve inter1nittently exposed to compression to assist the pressure fluid acting against the pressure surface of smaller area to throw the valve.

2. In a fluid actuated rock drill, the combination of a cylinder and a hammer piston therein, a valve chest having a valve chamber, inlet passages leading from the valve cham her to the cylinder, a valve in the valve chest comprising a body portion and an intermediate guide flange, a passage in the valve constantl conveying pressure fluid into the valve cham er, opposed differential pressure surfaces on the valve constantly exposed to pressure fluid for throwing the valve, ahead on one end of the valve over which pressurefluid flows to one inlet passage, and-an actuating surface on the end of the valve ii'itern'iittently exposed to compression to assist the pressure .fluid acting against the pressure surface of smaller area to throw the valve.

3. In a fluid actuated roclr drill, the combination of a cylinder and a hammer piston therein, a valve chest having a valve chamber, front and inlet passages leading from the valve chamber to the cylinder, a valve in the valve chamber comprising a body portion and an intermediate guide flange,.a passage in the valve to convey pressure fluid into the valve chamber, a'constant pressinre surface on one end of the valve across which pressurefluid flows to the front inlet passage, an opposing-constant pressure surface on the guide flange and of smaller area than the first said pressure surface, a head on the end of the valve over which pressure fluid flows to the rear inlet passage, and an actuating surface on the end of the valve adj acent the head and intermittently exposed to compression to assist the pressure fluid acting against the smaller pressure surface to throw the valve.

In testimony whereof I have signed this specification.

VVILLIAh/L A. SMITH, J n.

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